Vacuum brazing metallic honeycomb

Why We Braze Metal Honeycomb Instead of Gluing It

Two ways to make metal honeycomb. One we braze. One we don't. They look the same on day one. Month one. Maybe year one. After that? Not even close. Here's why we never glue.

Brazing Is Metal to Metal

Furnace heat fuses the layers together. No glue. No adhesive. Just solid joints.

Glued honeycomb is metal held together with... glue. That's where the trouble starts.

Brazed structure moves as one piece. Load transfers through joints the same as through the foil. No weak spots to find. With glue, the glue is always the weak spot.

Conductivity Has No Gaps

Honeycomb shields because the metal cells make a path for current. No breaks, no gaps.

Brazed joint is metal to metal. Current goes straight through. Glued joint has adhesive in between. Adhesive doesn't conduct. RF finds the gaps.

Brazed conducts every direction. Glued only works along the foil. At 3‑6 GHz, that's the difference between 95 dB and 60 dB.

Glue Doesn't Last

Glue holds when it's new. Then heat cycles start. Metal expands and contracts. Glue doesn't move the same way. After hundreds of cycles, the bond fatigues. Micro‑gaps open.

Vibration does the same. Glue gets brittle. Cracks. Loosens.

Moisture gets into glue. Swells it. Weakens it.

Brazed joints don't do any of that. Metal is fused. Nothing to fatigue, crack, or soak up.

Heat Kills Glue

Jet engines use vacuum brazed honeycomb. 760°C and above. Glue would be gone at those temps. It breaks down long before the metal softens.

Bodycote's brazed felt‑metal seals run at 760°C. Glue doesn't exist at that temperature. It's not a thing.

Joint Is Stronger Than the Metal

Brazed honeycomb fractures in the core, not at the joint. The bond is stronger than the base material. For titanium honeycomb, brazing can bump compressive strength 57% and elastic modulus 26%. Glue joints are always the weak link. Always.

Shielding Doesn't Drift

Brazed panel gives 90‑110 dB at 3‑6 GHz. Glued panel from the same spec? 60‑85 dB. That's a 30‑50 dB gap.

Real example: outdoor 5G cabinet. Bonded aluminum vent replaced with vacuum brazed multi‑stack aluminum. Shielding improved 18‑25 dB at 2‑6 GHz. Same cabinet. Same frequency. Different bond.

The honeycomb didn't change. The bond did.

We Don't Use Flux

Vacuum brazing doesn't need flux. Flux left inside can cause corrosion. Vacuum pulls it all out. Cleaner bonds. Stronger bonds.

Bottom Line

Brazed honeycomb is one piece of metal. Glued is metal with glue in between.

Brazed conducts everywhere. Glued only along the foil.

Brazed stays stable for years. Glued drifts as glue fatigues.

Brazed handles heat. Glue doesn't.

Brazed gives you 90‑110 dB. Glued gives you 60‑85 dB.

We braze everything we make. That's what we do.